The present invention relates to thread cutting inserts which may be detachably mounted on a tool holder for cutting a workpiece. Cutting insets of this type are generally made of cemented metal carbide and are formed by pressing and sintering techniques.
In the type of cutting inserts referred to herein, it is desirable to have an indexable insert which presents a positive rake cutting edge to the working piece.
U.S. Pat. No. 3,885,281 to Stambler describes an insert having both longitudinally curved and transversally curved channels along the side edges of the insert meeting at the corners of the insert. At each corner of the insert, V-shaped shallow grooves are depressed into the merging portions of the deeper longitudinal channels to provide chip control for shallow depth cuts.
U.S. Pat. No. 3,786,541 to Lundgren relates to a cutting insert having chip breakers in two stages wherein the cutting edge and the associated chip breaker describe a curve of a particular description.
U.S. Pat. No. 3,786,540 describes an insert having chip control groove extending along a side surface. The width of the groove describes a compound curve such that the width varies along the length of the side.
U.S. Pat. No. 3,399,442 to Jones describes an insert having chip control groove along the entire outer edge comprising an inner and outer region. The outer region is concave in cross-section.
U.S. Pat. No. 4,335,984 to Zweekly describes an insert having a plurality of breaking depressions in the chip breaker surface adjacent to the cutting corner.
U.S. Pat. No. 4,273,480 describes a succession of chip control recesses formed on the cutting face at the outer periphery along the cutting edge. The chip control recesses are generally spherical and may intersect or contact each other as well as the cutting edge.
U.S. Pat. No. 4,215,957 discloses depressions which are generally rectangular with inner corners spaced from the cutting edge.
U.S. Pat. No. 4,281,430 to Hellnick relates to an apparatus for machining pipe collars having internally tapered coaxial threads with a thread cutting tool having first and second thread topping forming portions defined on opposite sides of the thread groove-forming tooth. U.S. Pat. No. 4,531,863 to Smith et al relates to a thread cutting apparatus having multiple thread cutting profiles.
U.S. Pat. No. 4,572,713 to Schmidt relates to a threading insert having a plurality of cutting teeth along an edge. The recesses between successive teeth become progressively deeper in a direction away from the intersection of the edges.